Systems and Methods to Control Variable Stator Vanes in Gas Turbine Engines

ABSTRACT

Embodiments of the present application include a variable stator vanes control mechanism for a gas turbine engine. The control mechanism may include a moveable actuation rod in operative communication with a gear ring such that movement of the actuation rod drives the gear ring. The control mechanism may also include a first plurality of variable stator vanes disposed on a first side of the gear ring, the first plurality of variable stator vanes comprising gear stems in operative communication with the gear ring. Moreover, the control mechanism may include a second plurality of variable stator vanes disposed on a second side of the gear ring, the second plurality of variable stator vanes comprising gear stems in operative communication with the gear ring.

FIELD OF THE INVENTION

Embodiments of the present application relate generally to gas turbineengines and more particularly to systems and methods to control variablestator vanes in gas turbine engines.

BACKGROUND OF THE INVENTION

During operation of a gas turbine engine using a multi-stage axialcompressor, a turbine rotor is turned at high speeds by a turbine sothat air is continuously induced into the compressor. The air isaccelerated by rotating blades and swept rearwards onto adjacent rows ofvariable stator vanes. Each rotor blade/variable stator vane stageincreases the pressure of the air.

In addition to translating the kinetic energy of the air into pressure,the variable stator vanes also serve to correct the deflection given tothe air by the rotor blades and to present the air at the correct angleto the next stage of rotor blades. Pivoting the variable stator vanespermits the flow capacity of the compressor or turbine to be changed,thereby ensuring that the flow capacity is always at an optimum valuefor the particular operating conditions of the gas turbine engine.Accordingly, there is a need to control the angle of the variable statorvanes.

BRIEF DESCRIPTION OF THE INVENTION

Some or all of the above needs and/or problems may be addressed bycertain embodiments of the present application. According to oneembodiment, there is disclosed a variable stator vanes control mechanismfor a gas turbine engine. The control mechanism may include a moveableactuation rod in operative communication with a gear ring such thatmovement of the actuation rod drives the gear ring. The controlmechanism may also include a first plurality of variable stator vanesdisposed on a first side of the gear ring. The first plurality ofvariable stator vanes may include gear stems in operative communicationwith the gear ring. Moreover, the control mechanism may include a secondplurality of variable stator vanes disposed on a second side of the gearring. The second plurality of variable stator vanes may include gearstems in operative communication with the gear ring.

According to another embodiment, there is disclosed a method to controlvariable stator vanes in a gas turbine engine. The method may includeactuating a moveable actuation rod in operative communication with agear ring such that movement of the actuation rod drives the gear ring.The method may also include driving a first plurality of variable statorvanes disposed on a first side of the gear ring. The first plurality ofvariable stator vanes may include gear stems in operative communicationwith the gear ring. Moreover, the method may include driving a secondplurality of variable stator vanes disposed on a second side of the gearring. The second plurality of variable stator vanes may include gearstems in operative communication with the gear ring.

Further, according to another embodiment, there is disclosed a variablestator vanes control mechanism for a gas turbine engine. The gas turbineengine may include a compressor having a compressor casing. The controlmechanism may include a moveable actuation rod in operativecommunication with a gear ring such that movement of the actuation roddrives the gear ring about the compressor casing. The control mechanismmay also include a first plurality of variable stator vanes disposed ona first side of the gear ring. The first plurality of variable statorvanes may include gear stems in operative communication with the gearring by way of a plurality of respective connecting gears. Moreover, thecontrol mechanism may include a second plurality of variable statorvanes disposed on a second side of the gear ring. The second pluralityof variable stator vanes may include gear stems in operativecommunication with the gear ring. Accordingly, the first plurality ofvariable stator vanes and the second plurality of variable stator vanesmay be in operative communication with the gear ring such that theyrotate in similar directions.

Other embodiments, aspects, and features of the invention will becomeapparent to those skilled in the art from the following detaileddescription, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the accompanying drawings, which are notnecessarily drawn to scale, and wherein:

FIG. 1 is a schematic of an example diagram of a gas turbine engine witha compressor, a combustor, and a turbine, according to an embodiment.

FIG. 2 is a schematic of an example portion of a compressor assembly,according to an embodiment.

FIG. 3 is a perspective view of a portion of a compressor assembly,according to an embodiment.

FIG. 4 is a perspective view of a portion of a compressor assembly,according to an embodiment.

FIG. 5 is a perspective view of a portion of a compressor assembly,according to an embodiment.

FIG. 6 is a perspective view of a portion of a compressor assembly,according to an embodiment.

FIG. 7 is a perspective view of a portion of a compressor assembly,according to an embodiment.

FIG. 8 is a perspective view of a portion of a compressor assembly,according to an embodiment.

FIG. 9 is a perspective view of a portion of a compressor assembly,according to an embodiment.

FIG. 10 is a perspective view of a portion of a compressor assembly,according to an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Illustrative embodiments will now be described more fully hereinafterwith reference to the accompanying drawings, in which some, but not allembodiments are shown. The present application may be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Like numbers refer to like elementsthroughout.

Illustrative embodiments are directed to, among other things, systemsand methods to control variable stator vanes in gas turbine engines.FIG. 1 shows a schematic view of a gas turbine engine 10 as may be usedherein. As is known, the gas turbine engine 10 may include a compressor12. The compressor 12 compresses an incoming flow of air 14. Thecompressor 12 delivers the compressed flow of air 14 to a combustor 16.The combustor 16 mixes the compressed flow of air 14 with a pressurizedflow of fuel 18 and ignites the mixture to create a flow of combustiongases 20. Although only a single combustor 16 is shown, the gas turbineengine 10 may include any number of combustors 16. The flow ofcombustion gases 20 is in turn delivered to a turbine 22. The flow ofcombustion gases 20 drives the turbine 22 so as to produce mechanicalwork. The mechanical work produced in the turbine 22 drives thecompressor 12 via a shaft 24 and an external load 26 such as anelectrical generator and the like.

The gas turbine engine 10 may use natural gas, various types of syngas,and/or other types of fuels. The gas turbine engine 10 may be any one ofa number of different gas turbine engines offered by General ElectricCompany of Schenectady, N.Y., including, but not limited to, those suchas a 7 or a 9 series heavy duty gas turbine engine and the like. The gasturbine engine 10 may have different configurations and may use othertypes of components.

Other types of gas turbine engines also may be used herein. Multiple gasturbine engines, other types of turbines, and other types of powergeneration equipment also may be used herein together.

FIG. 2 depicts a section of the compressor 12 of the gas turbine engine10 of FIG. 1. The compressor 12 includes a tubular casing 28. Sets ofvariable stator vanes 30 are mounted within the casing 28circumferentially about the central axis of the compressor 12.Corresponding sets of rotor vanes 32 are mounted downstream of each setof variable stator vanes 30. Each variable stator vane 30 terminates atthe casing 28 in a stem 34. The stem 34 is rotatable in a bush bearing36 on the outside of the casing 28.

Located externally of the casing 28 and adjacent to each set of variablestator vanes 30 are unison rings 38 extending circumferentially aboutthe casing 28. The vane stems 34 of each set of variable stator vanes 30are connected to the corresponding unison ring 38 by a respective lever40. One end of the lever 40 is clamped to the end of the vane stem 34 bya bolt 42 so that there is no relative movement between the stem 34 andthe lever 40. The other end of the lever 40 is connected to the unisonring 38 by a pin 44 rotatable in a bush bearing located in the unisonring 38.

The unison ring 38 is arranged so that it may be rotated about thecentral axis of the compressor section 12 in either direction of arrow9. Consequently, rotation of the unison ring 38 causes rotation of eachvariable stator vane 30 via the levers 40 and thus enables the variablestator vanes 30 to assume required angles of incidence to the incomingair.

FIGS. 3 and 4 depict an embodiment of a variable stator vanes controlmechanism 100. The variable stator vanes control mechanism 100 enablesthe transfer of motion from one unison ring to another using only oneactuator. The variable stator vanes control mechanism 100 may include amoveable actuation rod 102. The moveable actuation rod 102 may be inoperative communication with a first unison ring 104 such that movementof the actuation rod 102 drives the first unison ring 104 in a firstdirection 106 about the central axis of the casing 108. Rotation of thefirst unison ring 104 causes rotation of each variable stator vane 110connected to the first unison ring by the levers 112.

The variable stator vanes control mechanism 100 may also include a bellcrank mechanism 114. The bell crank mechanism 114 may be in operativecommunication with the first unison ring 104. The bell crank mechanism114 may also be in operative communication with a second unison ring 116such that movement of the first unison ring 104 in the first direction106 translates movement, by way of the bell crank mechanism 114, to thesecond unison ring 116 in a second direction 118 that is opposite thefirst direction 106 of the first unison ring 104. Rotation of the secondunison ring 116 causes rotation of each variable stator vane 110connected to the second unison ring 116 by the levers 112.

Still referring to FIGS. 3 and 4, the bell crank mechanism 114 mayinclude a pivot 120, a first turnbuckle 122, and a second turnbuckle124. The first turnbuckle 122 operatively connects the first unison ring104 to the pivot 120. Similarly, the second turnbuckle 124 operativelyconnects the second unison ring 116 to the pivot 120. The firstturnbuckle 122 and the second turnbuckle 124 are attached to the pivot120 such that rotation of the pivot 120 drives the first turnbuckle 122and the second turnbuckle 124 in opposite directions.

In operation, the movable actuator rod 102 actuates the first unisonring 104 thereby rotating the first unison ring 104 in the firstdirection 106 about the casing 108. As the first unison ring 104 rotatesabout the casing 108 in the first direction 106, it drives the firstturnbuckle 122. The first turnbuckle 122 then applies a pivoting forceto the pivot 120. The pivoting of the pivot 120 causes the secondturnbuckle 124 to drives the second unison ring 116 thereby causing thesecond unison ring 116 to rotate in the second direction 118 about thecasing 108. In this embodiment, the second direction 118 and the firstdirection 106 are opposite of each other. The rotation of the firstunison ring 104 and the second unison ring 116 causes the respectivevariable stator vanes 110 attached to each unison ring to rotate inopposite directions due to the movement of the levers 112. Accordingly,the angle of the variable stator vanes 110 may be adjusted with thevariable stator vanes control mechanism 100.

As described above, the first direction 106 and the second direction 118are relative to each other. Accordingly, the first direction 106 and thesecond direction 118 may be any direction about the casing 108.Moreover, the moveable actuation rod 102 may be in operativecommunication with the first unison ring 104, the second unison ring106, or the bell crank mechanism 114.

In certain embodiments, the bell crank mechanism 114 may be at leastpartially secured to the casing 108 of the compressor. In otherembodiments, the moveable actuator rod 102 may be at least partiallysecured to the casing 108 of the compressor. One will appreciate,however, that the bell crank mechanism 114 and the moveable actuator rod102 may be at least partially secured at any location on or about thegas turbine engine.

A relative movement between the first unison ring 104 and the secondunison ring 116 and the angle of the variable stator vanes 110 may beadjusted by varying the dimensions of the pivot 12, the first turnbuckle122, and the second turnbuckle 124. Moreover, the angle of the variablestator vanes 110 may be varied by varying the length of the levers 112.

In an embodiment, as depicted in FIG. 5, the variable stator vanescontrol mechanism 100 may enable the transfer of motion from one unisonring to another using only one actuator. In this embodiment, however,the first unison ring and the second unison ring may rotate in the samedirection. For example, the bell crank mechanism 114 may include a pivot120, a first turnbuckle 122, and a second turnbuckle 124. The firstturnbuckle 122 operatively connects the first unison ring 104 to thepivot 120. Similarly, the second turnbuckle 124 operatively connects thesecond unison ring 116 to the pivot 120. The first turnbuckle 122 andthe second turnbuckle 124 may be attached to the pivot 120 such thatrotation of the pivot 120 drives the first turnbuckle 122 and the secondturnbuckle 124 in the same direction. Accordingly, in operation, themovable actuator rod actuates the first unison ring 104 thereby rotatingthe first unison ring 104 in a first direction 106 about the casing 108.As the first unison ring 104 rotates about the casing 108 in the firstdirection 106, it drives the first turnbuckle 122. The first turnbuckle122 then applies a pivoting force to the pivot 120. The pivoting of thepivot 120 causes the second turnbuckle 124 to drive the second unisonring 116 thereby causing the second unison ring 116 to rotate in thefirst direction about the casing 108. The rotation of the first unisonring 104 and the second unison ring 116 causes the respective variablestator vanes 110 attached to each unison ring to rotate in the samedirection due to the movement of the levers 112.

The embodiments as depicted in FIGS. 3-5 may include one or moreadditional unison rings in operative communication with the bell crankmechanism such that movement of the first unison ring in the firstdirection drives the one or more additional unison rings in the first orsecond direction respectively.

FIG. 6 depicts an embodiment of a variable stator vanes controlmechanism 200. The variable stator vanes control mechanism 200 enablesthe transfer of motion from one unison ring to another using only oneactuator. The variable stator vanes control mechanism 200 may include amoveable actuation rod 202 in operative communication with a firstunison ring 204. The moveable actuation rod 202 may actuate the firstunison ring 204. The variable stator vanes control mechanism 200 mayalso include a linkage 206 in operative communication with the firstunison ring 204 and a second unison ring 208 such that movement of thefirst unison ring 204 drives the second unison ring 208. This embodimentis similar to the previously described embodiments, except that it doesnot include the bell crank mechanism. Instead, this embodiment providesa direct linkage 206 between the unison rings 204 and 208. Accordingly,in this embodiment, the linkage 206 translates movement from theactuated first unison ring 204 to the second unison ring 208 in the samedirection. In certain aspects, the linkage 206 may pull the secondunison ring 208. In other aspects, the linkage 206 may push the secondunison ring 208.

Still referring to FIG. 6, in operation, the movable actuator rod 202 isattached to the casing 210 and actuates the first unison ring 204thereby rotating the first unison ring 204 about the casing 210. As thefirst unison ring 204 rotates about the casing 210, it drives thelinkage 206. The linkage 206 may be a turnbuckle. The linkage 206 thenapplies a force to the second unison ring 208 thereby causing the secondunison ring 208 to rotate about the casing 210. In this embodiment, thefirst unison ring 204 and the second unison ring 206 rotate in the samedirection about the casing 210. The rotation of the first unison ring204 and the second unison ring 206 causes the respective variable statorvanes attached to each unison ring by way of the respective levers 212to rotate. Accordingly, the angle of the variable stator vanes may beadjusted with the variable stator vanes control mechanism 200.

The embodiment as depicted in FIG. 6 may include one or more additionalunison rings in operative communication with one or more additionallinkages such that movement of the first unison ring in the firstdirection drives the one or more additional unison rings respectively.

FIGS. 7 and 8 depict an embodiment of a variable stator vanes controlmechanism 300. The variable stator vanes control mechanism 300 enablesthe actuation of multiple unison rings using only one actuator. Thevariable stator vanes control mechanism 300 may include a moveableactuation rod 302. The moveable actuation rod 302 may be in operativecommunication with a torque shaft 304 such that the movable actuationrod 302 rotates the torque shaft 304. A first unison ring 306 may be inoperative communication with the torque shaft 304 via a turnbuckle 305such that rotation of the torque shaft 304 drives the first unison ring306 in a first direction 308 about a central axis of the casing 310.Rotation of the first unison ring 306 causes rotation of each variablestator vane 312 connected to the first unison 306 ring by the levers314. Similarly, a second unison ring 316 may be in operativecommunication with the torque shaft 304 via a turnbuckle 307 such thatrotation of the torque shaft 304 drives the second unison ring 316 in asecond direction 318 about the central axis of the casing 310. Rotationof the second unison ring 316 causes rotation of each variable statorvane 312 connected to the second unison 316 ring by the levers 314.

As described above, the first direction 308 and the second direction 318are relative. The first direction 308 and the second direction 318 maybe the same direction or different directions about the casing 310. Forexample, in embodiments where the first direction and the seconddirection are the same, the turnbuckles 305 and 307 may be attached onthe same side of the torque shaft. Conversely, in embodiments where thefirst direction and the second direction are different, the turnbuckles305 and 307 may be attached on opposite sides of the torque shaft. Thefirst direction 308 and the second direction 318 may be any directionabout the casing 310. Moreover, the moveable actuation rod 302 may be inoperative communication with the first unison ring 306, the secondunison ring 316, or the torque shaft 304.

In operation, the movable actuator rod 302 is attached to the casing 310and actuates the torque shaft 304 thereby rotating the torque shaft 304.The turnbuckle 305 connects the first unison ring 306 to the torqueshaft 304, and the turnbuckle 307 connects the second unison ring 316 tothe torque shaft 304. As the torque shaft 304 rotates, the turnbuckles305 and 307 drive the first unison ring 306 and the second unison ring316 about the compressor casing 310. The rotation of the first unisonring 306 and the second unison ring 316 causes the respective variablestator vanes attached to each unison ring by the respective levers 314to rotate. Accordingly, the angle of the variable stator vanes may beadjusted with the variable stator vanes control mechanism 300. One willappreciate that one or more additional unison rings may be incommunication with the torque shaft by one or more respectiveturnbuckles.

In certain embodiments, the moveable actuator rod 302 may be at leastpartially secured to the casing 310 of the compressor. One willappreciate, however, that the moveable actuator rod 302 may be at leastpartially secured at any location on or about the gas turbine engine.Moreover, the torque shaft 304 may be rotatably supported about thecasing 310 of the compressor by a support structure 320. The supportstructure 320 may be any configuration that facilitates the rotation ofthe torque shaft about the compressor casing 310.

FIGS. 9 and 10 depict an embodiment of a variable stator vanes controlmechanism 400. The variable stator vanes control mechanism 400 enablesthe actuation of two variable stator vanes stages using only oneactuator and a system of gears. The actuator engages the gear systemwhich engages the two stages of variable stator vanes thereby adjustingthe variable stator vanes.

The variable stator vanes control mechanism 400 may include a moveableactuation rod 402. The moveable actuation rod 402 may be attached to thecasing 404 or any other location on or about the gas turbine engine. Themoveable actuation rod 402 may also be attached to a gear ring 406. Thegear ring 406 may be disposed about the compressor casing 404 such thatthe gear ring 406 rotates about the compressor casing 404 when actuatedby the moveable actuation rod 402. A rub block 408 may be disposedbetween the casing 404 and the gear ring 406 to facilitate smoothrotation of the gear ring 406 about the casing 404.

A number of variable stator vanes 410 may be disposed on a first side412 and a second side 414 of the gear ring 406. The variable statorvanes 410 form a first compressor stage and a second compressor stagerespectively on each side of the gear ring 406. The variable statorvanes 410 may include gear stems 416. The gear stems 416 may be inoperative communication with the gear ring 406.

In operation, the movable actuation rod 402 is attached to the casing404 and actuates the gear ring 406 thereby rotating the gear ring 406about the casing 404. The gear stems 416 of the variable stator vanes410 are in operative communication with the gear ring 406 such that asthe gear ring 406 rotates about the casing 404, the gear stems 416 ofthe variable stator vanes 410 are rotated. The rotation of the gearstems 416 adjusts the angle of the variable stator vanes 410.

In certain embodiments, the rotation of the variable stator vanes 410may be controlled by the addition of gears or gear train type mechanismsoperatively disposed between the gear stems and the gear ring. Forexample, as depicted in FIGS. 9 and 10, additional gears 418 areoperatively disposed between the gear ring 406 and the respective gearstems 416 of the first compressor stage. The addition of additionalgears 418 enables the first compressor stage of variable stator vanesand the second compressor stage of variable stator vanes to rotate inthe same direction. In contrast, if the gear stems 416 of the variablestator vanes 410 were in direct communication with the gear ring 406,the variable stator vanes 410 would rotate in opposite directions.

One will appreciate that any number of additional gears or gear traintype mechanisms may be operatively disposed between the gear ring andthe gear stems to facilitate a desired rotation. Moreover, the gearratio and the number of gear teeth may be adjusted to control theschedule between variable stator vane stages.

Although embodiments have been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the disclosure is not necessarily limited to the specific featuresor acts described. Rather, the specific features and acts are disclosedas illustrative forms of implementing the embodiments.

That which is claimed:
 1. A variable stator vanes control mechanism fora gas turbine engine, comprising: a gear ring; a moveable actuation rodin operative communication with the gear ring such that movement of theactuation rod drives the gear ring; a first plurality of variable statorvanes disposed on a first side of the gear ring, the first plurality ofvariable stator vanes comprising a first plurality of respective gearstems in operative communication with the gear ring; and a secondplurality of variable stator vanes disposed on a second side of the gearring, the second plurality of variable stator vanes comprising a secondplurality of respective gear stems in operative communication with thegear ring.
 2. The control mechanism of claim 1, wherein the firstplurality of variable stator vanes is in operative communication withthe gear ring by way of a gear train.
 3. The control mechanism of claim1, wherein the second plurality of variable stator vanes is in operativecommunication with the gear ring by way of a gear train.
 4. The controlmechanism of claim 1, wherein the first plurality of variable statorvanes and the second plurality of variable stator vanes are in operativecommunication with the gear ring such that they rotate in similardirections.
 5. The control mechanism of claim 1, wherein the firstplurality of variable stator vanes and the second plurality of variablestator vanes are in operative communication with the gear ring such thatthey rotate in opposite directions.
 6. The control mechanism of claim 1,wherein the gear ring is disposed about a rub block.
 7. The controlmechanism of claim 1, wherein the gear ratio is adjusted to control theschedule between variable stator vane stages.
 8. The control mechanismof claim 1, wherein the number of teeth on the gears is adjusted tocontrol the schedule between variable stator vane stages
 9. The controlmechanism of claim 1, wherein the moveable actuator rod is at leastpartially secured to a casing of a compressor.
 10. The control mechanismof claim 1, wherein the movable actuator drives at least two variablestator vane stages.
 11. A method to control variable stator vanes in agas turbine engine, comprising: actuating a moveable actuation rod inoperative communication with a gear ring such that movement of theactuation rod drives the gear ring; driving a first plurality ofvariable stator vanes disposed on a first side of the gear ring, thefirst plurality of variable stator vanes comprising a first plurality ofrespective gear stems in operative communication with the gear ring; anddriving a second plurality of variable stator vanes disposed on a secondside of the gear ring, the second plurality of variable stator vanescomprising a second plurality of respective gear stems in operativecommunication with the gear ring.
 12. The method of claim 11, furthercomprising: rotating the first plurality of variable stator vanes andthe second plurality of variable stator vanes are in similar directions.13. The method of claim 11, further comprising: rotating the firstplurality of variable stator vanes and the second plurality of variablestator vanes are in opposite directions.
 14. The method of claim 11,further comprising: adjusting the gear ratio and the number of gearteeth to control the schedule between variable stator vane stages.
 15. Avariable stator vanes control mechanism for a gas turbine engine,comprising: a compressor having a compressor casing; a gear ringdisposed about the compressor casing; a moveable actuation rod inoperative communication with the gear ring such that movement of theactuation rod drives the gear ring about the compressor casing; a firstplurality of variable stator vanes disposed on a first side of the gearring, the first plurality of variable stator vanes comprising a firstplurality of respective gear stems in operative communication with thegear ring by way of a plurality of respective connecting gears; and asecond plurality of variable stator vanes disposed on a second side ofthe gear ring, the second plurality of variable stator vanes comprisinga second plurality of respective gear stems in operative communicationwith the gear ring; wherein the first plurality of variable stator vanesand the second plurality of variable stator vanes are in operativecommunication with the gear ring such that they rotate in similardirections.
 16. The control mechanism of claim 15, wherein the gear ringis disposed about a rub block.
 17. The control mechanism of claim 15,wherein the gear ratio is adjusted to control the schedule betweenvariable stator vane stages.
 18. The control mechanism of claim 15,wherein the moveable actuator rod is at least partially secured to acasing of a compressor.
 19. The control mechanism of claim 15, whereinthe movable actuator rod drives at least two variable stator vanestages.
 20. The control mechanism of claim 15, wherein the number ofteeth on the gears is adjusted to control the schedule between variablestator vane stages